ANNAPOLIS — In a harshly worded letter condemning a proposed legislative inquiry into his administration’s firing practices, Gov. Robert L. Ehrlich Jr. told legislative leaders yesterday that his “willingness to endure these contemptible attacks, dismissing them merely as politics-as-usual, is over.”

The governor said the purpose of the investigation “is becoming clear: to unfairly harass this administration.”

Mr. Ehrlich, a Republican, renewed his demand that House Speaker Michael E. Busch and Senate President Thomas V. Mike Miller Jr., both Democrats, remove “biased legislators” from the committee, although his letter did not list names.

“This is an orchestrated campaign, being led by partisan political opponents, misstating and ignoring facts, attempting to challenge the ethical and legal integrity of the Ehrlich administration,” the governor said.

Mr. Miller and Mr. Busch appointed a committee of eight Democrats and four Republicans to look into accusations that the governor’s aides fired some employees who did not hold political positions because they were Democrats who were not considered loyal to Mr. Ehrlich.

Both leaders said they would continue with the inquiry, pledging that it will be fair and nonpartisan.

Mr. Miller, who had not seen the governor’s letter when questioned by the Associated Press, said he does not know why Mr. Ehrlich responded in such strong terms.

“I believe the governor and his staff are overly sensitive. I’m not sure what they are trying to cover up or hide and why they don’t recognize there is a problem that needs to be resolved,” Mr. Miller said.

“We need to move forward as quickly as possible to have this whole matter concluded by the next legislative session so that we can put our heads together to work on legislation to benefit the people of the state of Maryland,” he said.

[The Washington Times first reported June 29 that two Democrats on the investigative committee expressed opinions about the legality of the administration’s actions before the committee had even convened.

[Sen. Paula C. Hollinger, Baltimore County Democrat, was quoted as saying the firings were “against the law.”]

Mr. Ehrlich’s letter yesterday was the latest in a series of exchanges between the administration and lawmakers.

Mr. Miller and Mr. Busch said the goal of the inquiry will be to look at complaints about the firing of state employees with a goal of determining whether the law needs to be changed to protect workers from being improperly fired by governors.

“We’re not going to condemn this process before it starts,” Mr. Busch said.

He said it is a fact that some long-term employees in nonpolitical positions were fired without cause. “The question is, was there a coordinated campaign to remove state employees because of their political affiliation,” he said.

Mr. Busch said the six Senate members and six House members of the committee were chosen from among Democrats and Republicans who are held in high regard by their colleagues in both parties.

Mr. Busch and Mr. Miller said they do not relish the inquiry, which they hope to get under way by next month and have completed before the 2006 legislative session begins in January.